COGS 17 Lecture Notes - Lecture 7: Retinal Pigment Epithelium, Ganglion Cell, Amacrine Cell
4 Dec 2016
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Document Summary
Fovea (point of central focus), used to discriminate details. Optic nerve- leaves eyes, carries into brain, blind spot, where axons leave. Receptor cells are rearmost layer of retina, farthest away from incoming light, receptors respond to light. Both rods and cones have photo pigment embedded in outer segment. Outer segment embedded in pigment epithelium provides re-nourishment for neuron cells. Visual receptors are firing in the dark and turned off by light. The visual pathway of the retina is composed of receptors bipolars ganglions. Receptor cells: spontaneous (fires in the absence of input), graded potentials, inhibitory. Mnemonic: once you get to the ganglion, firing is all or none. Flow of ions in the absence of light. In dark, cgmp holds na+ gates open. This changes the polarity in cell, voltage dependent gates then open allowing for. Ca++ to enter and the nt to be released. Photons of light enter, interact with chemicals.
